Internal-combustion engine and the like



Sept. 9, 1924. 1,508,099,

.1. B. HAWLEY JR INTERNAL COMBUSTION ENGINE AND THE LIKE Filed Feb. 28. 1923 Patented Sept. 9, 1924.1 1

- UNITED STATE arar OFFICE.

JOHN B. mwLEY, an, orcomonnno srnmes, oonormno. 1

IIlTERNAL-COMBUSTION ENGINE AND THE Application'flled February 28, 192a. Serial mi. 621,787.

provementsv in pistons and cylinders for internal combustion engines. .The lnvention has reference particularly to certain improvements in the construction of those portions of'th'e piston and cylinder which are directly subjected tothe action of the gases at the instant of explosion. More particularly, the invention has reference to improvements in the construction of these parts, having for their main object the elimination or prevention of the formation of carbon deposit with its attendant disadvantages.

Inconnection with the foregoing objects, one feature of the invention relates to the provision of a relatively thin metal plating on those'portions of th surfaces most subject to carbon deposition, which plating of metal is of suchncomposition that the carbon will not readily adhere to the same under the conditions existing within the cylinder, and particularly within the combustion chamber. be made of brass or copper or other metal having a high heat conductivity, and the action may be still further improved by plating the same with silver or other precious metal.

A further feature of the invention relates to the provision of an arrangement such that the adhesion -of the carbon to the metal.

surface will be largely combated by the expansion and contraction which take place in such metal covering. 'This expansion and contraction of the metal covering will'be different inamount (usually greater) than the expansion and contraction of the carbon itself under the differences of temperature there existing, so that the natural tendenc will be for the carbon deposit to be perio ically loosened and broken away from the metal coating. In this way the carbon will be kept broken up and disengaged from the surfaces-0f the combustion chamber and piston head, and the carbon will be discharged For example, this metal plating may through the exhaust ports along with other scavenge effects. x

- In connection with the feature of conbating the deposit of carbon by the use of expansion and contraction, it is a further object of the invention to make provision for exaggerating this expansion and contraction as much as possible. For this purpose, another feature of the invention relates to the provision of a layer of relatively spongy material such as graphite or plaster of Paris between the surface of the cylinder orpiston head and the thin layer of carbon shedding material, such layer of graphite or plaster of Paris serving to permit an exaggerated amount of expansion and contraction of the carbon shedding? layer to take place, and thus materially im- I prove the deslred action.

In connection with the foregoing feature, it will noted that the intermediate layer of graphite or laster of Paris or othersuitable material serves not only to permit an' exaggerated amount of expansionand contraction of the carbon shedding material to take place, but also serves to provide a continuous backing or support for the same at all points and serves to provide a practi-. cally continuous medium ofattachment to the surface of-the combustion chamber or piston head, without at the same time materially interfering with the desired expan sion and contraction effect.

Other objects and uses of the invention will appear from a detailed description of the same, which consists in the features of construction and combinations of parts hereinafter described and claimed.

In the drawing: i

Figure 1 shows a longitudinal section through a cylinder and combustion chamber provided with. the features of the present invention, and also shows a piston in lace within the cylinder,-the top surface 0 the piston being provided with the carbon shedding layer of the present invention, and theisame being shown in section;

"Fig. 2 shows a section taken on the line 2-2 of Fig. 1, looking in the direction of the arrows, the carbon shedding surface being partly broken .awayto show the intermed1ate backing material.

' In the drawin the features of my invention have been sliown as applied in a-more or less diagrammatic manner, but, manifestly, the exact form and arrangement of the application of this 'feature will depend largely upon the exact form and arrangement of the cylinder and piston.

In the articular construction illustrated, the cylin er is .desi ated in its entirety by the numeral l, an the connecting rod by the numeral 5.

The upper portion of the cylinder is suitably formed to establish a combustion chamber 6 into which is inserted the spark plug 7. The upper end of the piston overrides slightly into the combustion chamber 6, and said combustion chamber has its cylindrical wall 8 counter bored in order to permit the overriding just mentioned.

lin order to prevent or minimize the deposition cit-carbon on the roof or walls of the combustion chamber as well as the top surface 10 of the piston, l adopt the expedient which ll will now explain more in detail. This consists in coating the top surface of the piston, and thewalls and roof of the combustion chamber, with a layer of metal such as brass or copper, or silver or other rare metal, which is possessed of the property of largely resistin the adhesion of carbon deposit. This is t e layer 11 overlying the top surface 10 of the piston, as Well as the layer 12 on the walls and roof of the combustion chamber. In some cases, it may be found desirable or advisable to provide such layer only on one or the other of these surfaces instead of all of them as illustrated in the drawing.

The use of such metals as silver for this layer is very desirable-and advantageous,

since experience demonstrates that this material, as well as others, will largely resist the stichng of carbon thereto, particularly at the temperatures at which the same is formed within the combustion chamber.

i The ability to resist carbon deposit is also greatly enhanced by the expansion and contraction of this metal coating .as compared to the normal and expected expansion and contraction of the 'uncoated surface. This difierence in expansion and contraction also amounts to an exaggerated difference of expansion andcontraction as compared to the expansion and contraction of the carbon de osit itself.

A further eature is that by the use of a coating of metal which is of relatively high heat conductivity, the same will expand and contract rapidly with the temperature changes which take place on the difl'erent port ons of the engine cycle, such rapid expension and contraction very materially asthe ability to resist carbon "deposit.

isexpansion and contraction efiect will be more readily appreciated when the violent extremes of temperature within the combustion chamber are considered; These ex- 'tremes of temperature variation cover many hundreds degree Fah. and occur with great rapidity.

In order to allow the carbon shedding surface to act to the best advantage in its resistance of carbon deposit, ll prefer to establish a layer of material 13 between the carbon shedding layer 11 and the piston head 10, and another layer 14 between the carbon shedding layer 12 and the walls and roof of the combustion chamber. These layers 13 and 14 are preferably composed 0T material which is of a somewhat yielding nature, so that it will suffer some distortion without rupture, and is also preferably of a nature which will adhere firmly to the carbon shedding layer as well as to the surface ofv the piston or of the combustion chamber as the case may be. Such materials include, for example, graphite and plaster of Paris. The materials used for the layers '13 and 14 are also preferably of a heat insulating nature, so that the changes of temperature, to which the carbon shedding layers are subjected, will be still further exaggerated with the additional beneficial results. Graphite and'pla-ster of Paris also respond to this particular desirable quality.

In order to reduce the cost of manufacture and at the same time make it possible to use silver or other precious metal as the surface which is directly subjected to the tendency. for carbon deposit, ll prefer to make each of the layers 11 and 12 of brass or copper or other high conductivity metal, and then silver plate the same, if the use of silver is determined upon.

The thickness of the layers 13 and 14: will depend largely upon the desires of the designers, but the same may be as much as onefourth of an inch thick. The layer of brass or copper or the. like maybe established thereon by plating to a thickness or, say, ten thousandths of an inch, and thereafter the plating of silver or the like may be used if desired. 1

lit is pointed out that when two metals are used for the layer, such as brass or copper, with a coating of silver, which metals have difi'erent co-eficients of thermal expansion, they will tend to cause the layer to flex with changes of tem erature, according to the principles whic are well understood in "connection with thermostats, for example. This flexing, when it occurs, will further assist the elimination fot carbon or the tendency to deposit carbdii.

In some cases it will be desirableto leave on both sides of it. In some cases, also, it

lltl

may be desirable to amalgamate the silver coating with mercury.

While I have herein shown and described only a single embodiment of the features of my present invention, and have only mentioned the use of certain materials for the carbon shedding surfaces and for the backing materials, still it will be understood that I do not limit myself to eitherthe construction shown or the materials mentioned herein, except as I may do so in the claims.

I claim:

1 The combination with the piston head and the walls and roof of the combustion chamber of an internal combustion engine, of a backing of plaster of Paris or the like substantially one-fourth inch thick on said surfaces, a coating of brass or the like substantially ten thousandths of an inch thick on said plaster of Paris backing, and a coating of silver or the like on the exposed surfaces of said brass or the like, whereby there is established a relatively thin covering of brass or the like for each of said surfaces attached thereto over substantially all of said surfaces and yieldable with respect to said surfaces with changes of temperature, and whereby said silver'coating serves effectively -to prevent adhesion of carbon to said surfaces, substantially as described.

2. The combination with the surfaces of the piston head and combustion chamber of an internal combustion engine, of a relatively thin layer of brass or the like in close proximity to each of said surfaces, a rela-v tively yieldable adhesive element intermediate between such layer and each of said surfaces, and a coating of silver or the like on the exposed face of said layer, whereby there is provided a relatively thin layer of metal adjacent to each of said surfaces and connection thereto but yieldable with respect thereto under change oftemperatures, and whereby the tendency towards the deposi-. tion of carbon on said surfaces is minimized, substantially as described.

3. The combination with the surfaces of the piston and combustion chamber of an internal combustion engine, of a relatively thin la er of metal in close proximity to each 0 said surfaces but separated therefrom and yieldable with respect thereto, means between said layer and said surfaces serving to support said layer in position with respect to said surfaces while permitting relative movement with changes of temperature, and a coating of silver or the like on the exposed face of said layer, whereby the tendency towards the deposition of carbon is minimized, substantially as described.

4. In an internal combustion engine, the combination with a surface subjected to the action of the combusting gases of the combustion chamber, of a layer of metal in close proximity to said surface but separated therefrom and yieldable with respect thereto with changesof temperature in the combustion chamber, a suitable backing between said surface and said layer permitting such movement with changes of temperature, and

a coating of silver or the like on the exposed face of said layer, whereby the tendency towards the deposition of carbon is minimized, substantially as described.

5. Inan internal combustion engine, the combination with a surface subject to the action of combusting gases within the combustion chamber, of a layer of metal in close proximity to said surface but yieldable with respect thereto with changes of temperature in the combustion chamber, and a suitable backing between said surface and said layer, whereby there is established a layer yieldable with respect to said surface with changes of temperature in the combustion chamber to thereby minimize the tendency .to deposit carbon, substantially as described.

6. In an internal combustion engine, the combination with a surface subject to the action of combusting gases within the combustion chamber, of a layer of metal in close proximity to said surface but yieldable with respect thereto with changes of temperature in the combustion chamber, said layer having a difierent co-efiicient of expansion with temperature change than that of the surface adjacent thereto, substantially as described.

7. In an internal combustion engine,-the combination with a surface subject to the action of combusting gases within the combustion chamber, of a coating of silver overlying said surface and directly subject to the action of the combusting gases, whereby the tendenc towards the deposition of carbon on sai tially as described.

surface is minimized, substan- 

